Sphingomyelin will be dispersed as liposomes, as mixed micelles of this lipid and a detergent and as a monolayer at an air-water interface and its interaction with sphingomyelinase will be studied. Attempts will be made to purify brain sphingomyelinase to homogeneity. A new brain isoenzyme which requires a divalent metal and brain lipases will be investigated. The nature of ganglioside dispersion which are utilized by enzymes will be studied using detergents.